Re: [PATCH 6.12.y] drm/amd/display: Wrap DCN32 phantom-plane allocation in DC_RUN_WITH_PREEMPTION_ENABLED

[Sasha Levin <sashal@kernel.org>]

> [How]
> Wrap the dc_state_create_phantom_plane() call with the
> DC_RUN_WITH_PREEMPTION_ENABLED() macro to allow preemption during
> this memory allocation.

> +#if !defined(DC_RUN_WITH_PREEMPTION_ENABLED)
> +#define DC_RUN_WITH_PREEMPTION_ENABLED(code) code
> +#endif

Thanks for the backport, but this isn't going to fix the BUG_ON on
6.12.y as-is. DC_RUN_WITH_PREEMPTION_ENABLED() only gained its real
definition in v6.16 (around the dc_fpu_preempt rework); it does not
exist on 6.12 at all. With the "!defined(...) -> identity" fallback
above, the wrap reduces to a plain call to dc_state_create_phantom_plane()
on this tree, which is exactly the pre-patch code path that hits
BUG_ON(in_interrupt()) in the vmalloc path.

So the backport as written is a no-op on 6.12.y and won't address the
DCN32 crash you're seeing. To actually fix it on 6.12.y we need the
underlying preempt-enabled-region mechanism, or a different
6.12-specific fix that allows the ~335 KiB allocation outside the
DC_FP_START()/DC_FP_END() region (for example by hoisting the
allocation, or using a smaller/preallocated buffer).

Could you put together a v2 along those lines?

-- 
Thanks,
Sasha